For efficient utilization of a water treatment filter, it is indispensable to provide an efficient mode for washing the filtration material or materials. The washing modes used up to now require a well distributed introduction of washing fluids, which are generally air and water, within the filtration mass.
For a better spreading and equidistribution, of the washing fluids one may use strainers or nozzles which are usually mounted inside the structure for supporting the filtration material. This structure, called a floor, can be in particular formed of reinforced concrete, in which case the arrangement of the cavities formed in the floor for housing the nozzles requires, during the preparation of the fllor, delicate and numerous interventions. In a general manner, the hole intended for receiving the nozzle fixation member can be made by setting in position small size devices, which may be made of steel, adapted for removed when the concrete has set, and then meticulously cleaned in order to be used again, or discarded. Moreover, the adjustment and emplacement of these elements require a lot of attention and care.